Portable line-boring machine



FIG. 1 is a top, front and right side perspective view of a portable line-boring machine showing my new design;

FIG. 2 is a front elevational view;

FIG. 3 is a rear elevational view;

FIG. 4 is a left side elevational view;

FIG. 5 is a top plan view; and,

FIG. 6 is a bottom plan view thereof.

FIG. 1 has been drawn on an enlarged scale with respect to FIGS. 2-6. 

The ornamental design for a portable line-boring machine, as shown. 